The identification of gene mutations causing disease lends new insight into the pathogenesis and etiology of the disorder under examination. In collaboration with NINDS and NHGRI we are performing a whole genome scan of families with a variety of neurological diseases. We assessed two families with Parkinson's disease (PD), a large kindred from Columbia with Blepharospasm and a family with dystonia associated with pain. The genome wide scan in these families is being performed in collaboration with the linkage analysis core of LNG using a 5cM linkage panel and is currently 80% complete. Data management and analysis is being performed using a custom database and linkage interface designed by the bioinformatics and computational biology core of LNG. We have identified a region of linkage within chromosome 4 in a large in-bred PD family, a region containing a segregating haplotype on chromosome 3 in the blepharospasm family and a segregating haplotype on chromosome 17 in the dystonia family. In collaboration with Drs Wood and Perez-Tur we identified the gene LRRK2 which underlies PARK8 linked Parkinson's disease. THis has subsequently been shown to cause >1% of sporadic PD and >5% of familial PD.